1. Field of the Invention
This invention relates to a composition comprising a homogeneous mixture or blend of an oxidation-curable type water-soluble resin; and a vinyl type polymer obtained by polymerizing a vinyl monomer or monomers in the presence of a neutralized, water-soluble product of an adduct between an amorphous polymer obtained by ring-opening polymerization of dicyclopentadiene and maleic acid or maleic anhydride.
2. Description of the Prior Art
As is well known, aqueous coating materials are noted as being one type of environmental pollution free or resource saving type of coating material. Synthetic resin emulsions are in wide use as resins for such aqueous coating material. However, such synthetic resin emulsion, of which vinyl acetate type or acrylic type emulsions are typical, are deficient for use in such coatings. Although these emulsions show excellent drying properties, their coating films undergo deterioration of water resistance after coating and drying, because of the use of an emulsifier or protective colloid upon polymerization. In addition, these emulsions are liable to form porous coating films because of their film forming mechanism, and the resulting film does not have sufficient luster and adhesiveness to be commercially useful.
The inventors have disclosed in Japanese patent application Ser. No. 114018/79, an invention relating to a vinyl type polymer emulsion, obtained by emulsion polymerization of a vinyl monomer or monomers in the presence of a netralized, water-soluble product of an adduct between an amorphous polymer obtained by ring-opening polymerization of dicyclopentadiene and having chain-like and cyclic carbon-to-carbon unsaturated double bonds within the monomer unit (hereinafter referred to as DCPD polymer) and maleic acid or maleic anhydride (maleinized DCPD polymer). This vinyl type polymer emulsion undergoes rapid oxidation curing and is excellent in water resistance and solvent resistance. However, it does not show satisfactory corrosion resistance and coating film luster due to its property of forming a porous surface which is characteristic of a water dispersible resin.
A possible alternative for removing such defects of a water-dispersible resin, may be mixing or a polymer emulsion with a general water soluble resin, which shows good luster, good adhesiveness and good pigment dispersing properties. However, a large amount of water soluble resin is necessary for removing the defects of polymer emulsions. The resulting coating film always has insufficient drying properties and insufficient solvent resistance, although the polymer emulsion itself may provide good drying properties and good solvent resistance.